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Author How to undine a value
Richard Heintze

2004-05-22, 11:31 am

I find I'm undefining variables my assigning an
unitialized variable to defined value to make it
undefined (as exemplified below).

Is there a better way to do this?

my $k;
for($i = 0; $i < $c; $i++){
if ( defined $k ){
print $x[$k];
my $t; # intentionally undefined
$k = $t; # undefine $k
} else {
$k = $i;
}
}

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Randy W. Sims

2004-05-22, 11:31 am

On 4/1/2004 11:46 PM, Richard Heintze wrote:

> I find I'm undefining variables my assigning an
> unitialized variable to defined value to make it
> undefined (as exemplified below).
>
> Is there a better way to do this?
>
> my $k;
> for($i = 0; $i < $c; $i++){
> if ( defined $k ){
> print $x[$k];
> my $t; # intentionally undefined
> $k = $t; # undefine $k
> } else {
> $k = $i;
> }
> }


undef $k;

see 'perldoc -f undef'

Regards,
Randy.


Wc -Sx- Jones

2004-05-22, 11:31 am

Richard Heintze wrote:
> my $t; # intentionally undefined
> $k = $t; # undefine $k



Just for clarity -

This isn't "undefining" it is
assignment of nothing to $k;

my $nothing;

print "\n\$nothing's Value: $nothing and
\$nothing's length ". length $nothing;

my $somthing = 100;

$somthing = $nothing;

print "\n\$somthing's Value: $somthing and
\$somthing's length ". length $somthing;


-Sx-
Wiggins D Anconia

2004-05-22, 11:31 am



> I find I'm undefining variables my assigning an
> unitialized variable to defined value to make it
> undefined (as exemplified below).
>
> Is there a better way to do this?
>
> my $k;
> for($i = 0; $i < $c; $i++){
> if ( defined $k ){
> print $x[$k];
> my $t; # intentionally undefined
> $k = $t; # undefine $k
> } else {
> $k = $i;
> }
> }
>


Unless this is a contrived example, just increment $i by 2 each loop.
If it is contrived then the other answers should work...

http://danconia.org


Wc -Sx- Jones

2004-05-22, 11:31 am

Wiggins d Anconia wrote:
>
>
> Unless this is a contrived example, just increment $i by 2 each loop.
> If it is contrived then the other answers should work...


Well, $c and @x were never defined/explained
by the time this contruct was presented.

--
-Sx-

[This message contains no user serviceabe code.]

use strict;
use warnings;
use diagnostics;

my (@x) = qw% But for sanities sake %;
my ($c, $i, $k, $t) = 2**32+1;

undef $k;

for($i=0, $c=2; $i<$c; $i=0) {

if ( defined $k ) {
print $x[$k];
$k = $t;
} else {
$k = $c;
}
}

__END__
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